Circuit arrangements used in normal communication semiconductor components, xDSL broadband transceivers for example, contain both analogue as well as digital components, of the two however, in particular, the analogue components for their function depend on a barrier layer temperature of a semiconductor circuit element. Typically satisfactory operation is guaranteed within a specific range of the barrier layer temperature, for example −40° C. to 125° C.
The barrier layer temperature is determined by the ambient temperature, the power consumption of the semiconductor circuit arrangement and the thermal resistance of the semiconductor circuit arrangement in its respective environment, so that provided the thermal resistance and the power consumption are known, it would be enough to measure the ambient temperature in order to guarantee that the communication semiconductor component is operating within the permitted range of the barrier layer temperature. According to the prior art the barrier layer temperature in a communication semiconductor component is not directly accessible to a user or to a control unit of a communication system, wherefore a permitted range of ambient temperature is normally specified in the data sheet of the communication semiconductor component. A disadvantage of this method is its limited accuracy, which is caused by the dependence of the thermal resistance on influences such as air draught generated by convection or fans, the layout and temperature of the printed circuit board, on which the communication semiconductor component is mounted as well as due to the fact that said influences and therefore the thermal resistance but also the ambient temperature are not the same for all communication semiconductor components installed in a device, for example a housing or switchgear cabinet. Moreover accurate determination of thermal resistance costs time and resources and requires detailed simulation of the thermal behaviour of the semiconductor circuit arrangement and its environment.